Sharp R-380D Service Manual page 16

R-380D
PROCEDURE
LETTER
RY1 and RY2 Relay Test
These relays are operated by D.C. voltage.
Check voltage at the relay coil with a D.C. voltmeter during the microwave cooking operation.
DC. voltage indicated ............... Defective relay.
DC. voltage not indicated ......... Check diode which is connected to the relay coil. If diode is good,
RELAY SYMBOL
CARRY OUT 4R CHECKS.
O PROCEDURES TO BE TAKEN WHEN THE FOIL PATTERN ON THE PRINTED WIRING BOARD
(PWB) IS OPEN
To protect the electronic circuits, this model is provided with a fine foil pattern added to the primary
on the PWB, this foil pattern acts as a fuse. If the foil pattern is open, follow the troubleshooting guide
given below for repair.
Problem: POWER ON, indicator does not light up.
CARRY OUT 3D CHECKS.
STEPS
1
2
3
4
NOTE: *At the time of making these repairs,
make a visual inspection of the varistor.
Check for burned damage and exam-
ine the transformer with a tester for the
presence of layer short-circuit (check
the primary coil resistance). If any ab-
normal condition is detected, replace
the defective parts.
CARRY OUT 4R CHECKS.
P AH SENSOR TEST
Checking the initial sensor cooking condition
(1) The oven should be plugged in at least two minutes before sensor cooking.
(2) Room temperature should not exceed 35˚C.
(3) The unit should not be installed in any area where heat and steam are generated. The unit should
not be installed, for example, next to a conventional surface unit. Refer to the "INSTALLATION
Instructions" .
(4) Exhaust vents are provided on the back of the unit for proper cooling and air flow in the cavity. To
permit adequate ventilation, be sure to install so as not to block these vents. There should be some
space for air circulation.
(5) Be sure the exterior of the cooking container and the interior of the oven are dry. Wipe off any
moisture with a dry cloth or paper towel.
(6) The Sensor works with food at normal storage temperature. For example, chicken pieces would
be at refrigerator temperature and canned soup at room temperature.
(7) Avoid using aerosol sprays or cleaning solvents near the oven while using Sensor settings. The
sensor will detect the vapour given of by the spray and turn off before food is properly cooked.
TEST PROCEDURES
control unit is defective.
OPERATIONAL VOLTAGE
RY1 APPROX. 25.0V D.C.
RY2 APPROX. 24.0V D.C.
OCCURRENCE
The rated AC voltage is not present between
Pin No. 2 of the 2-pin connector (A) and the
normal open terminal of the relay RY1.
The rated AC voltage is present to primary
side of low voltage transformer.
Only pattern at "a" is broken.
Pattern at "a" and "b" are broken.
COMPONENT TEST
CONNECTED COMPONENTS
Oven lamp / Turntable motor / Cooling fan motor
Power transformer
CAUSE OR CORRECTION
Check supply voltage and oven power cord.
Low voltage transformer or secondary circuit defective.
Check and repair.
*Insert jumper wire J1 and solder.
*Insert the coil RCILF2003YAZZ between "c" and "d".
c
14
d
b
(J1)
a